In correspondence chess you are allowed to use the opening book. However, I don't want to use it and from my experience, most correspondence players don't use it neither. But when you open the Analysis Tab in the browser (of course without engine - the engine does not exist there) to play some variants and you had the opening book open for the latest game analysis, lichess remembers that and you automatically see the book although you probably don't want. Wouldn't it be possible that when pressing the analysis button in a correspondance game, the book is automatically turned off and you have to actively activate it? In the lichess app it is like that btw.